> It shouldn't require casting from and to specific pointer types

You don't need to explicitly cast T* to void* (guaranteed to be safe), you only need to cast when converting out of void*.

The rules are basically the same as casting between pointer-to-derived-class and pointer-to-base-class and they make sense.

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uecker 2 hours ago | parent [-]

They make sense but reduce type safety, because once you add the cast the case might hide some real typing issue. I sympathize with the idea that the down-cast should be explicit though.

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spacechild1 an hour ago | parent [-]

> They make sense but reduce type safety

Yes, downcasting can be unsafe and should be used carefully, but what's the alternative? At least in C++ you can't cast between unrelated types without an explicit reinterpret_cast (or C-style cast).

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chrchang523 36 minutes ago | parent [-]

and you CAN use static_cast to convert from void*; this silently keeps working if you refactor the void* into a matching-type pointer later, while raising a compilation error if you refactor to a different-type pointer.

	▲	uecker 12 minutes ago \| parent [-]
		Yes, a static_cast would be safe, but then most C++ seems to use a C-style cast because it is less clunky and then is less safe than the corresponding C code. The issue is not that the downcast is unsafe (it is, but once you have a void pointer you already accepted this), but that it becomes even less safe by adding a C-style cast. It is also not clear what is gained by forcing programmers to add a cast. Void pointers should be used sparingly anyway.